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SortaSenator Bostonian

The Bostonian class seems to be becoming more popular in the UK, partly I am sure due to the low key competitions put on by the Impington club at their meetings. The models are a handy size, simple to build and can fly very well. The Impington club fly Bostonians with a 14 gram minimum weight rule (the same as the AMA outdoor rules), which makes the class accessible to anyone (it is not uncommon for entries to require ballast if they have been built too lightly)

Main rules are, 16 inch max. wing span, 3 inch max. chord. and all flying surfaces must be covered on both sides. 14 inch max. fuselage length, which must incorporate a box with dimensions 1.5" wide, 2.5" high and 3" long. Clear windows must be carried with a projected area of at least 1 square inch. At least two rotating wheels must be carried spaced at least 2.5 inches apart so the model can sit on its undercarriage and ROG.

Many designs are cartoon versions of full size aircraft, and some others are caricatures of larger free flight sport models. The idea for the SortaSenator came from the well known SortaKorda Bostonian, which I think is an extremely cute model, and I thought I would give the same treatment to my favourite Keil Kraft rubber duration model, the Senator. This was the first rubber model I ever got to fly properly, back in the 1960s, so I have happy memories of it.

One stumbling block was the requirement in the Bostonian rules for a pair of wheels, whereas the Senator famously only has a mono leg. The solution was to hide the two wheels in the sub fins, so the model rests on those at the back, with the single wheel at the front. The three upper spars of the wing are a bit excessive I suppose, but I wanted to preserve the charactor of the original. I thought they might have a useful turbulating effect as well.

I am grateful to Russ Lister for building the prototype, before I managed to get round to building one myself and the the photos here are of his model. One modification made as a result of Russ's experiences was to make the front windows a little smaller to strengthen the forward fuselage (useful if you fly head first into a sports hall wall). Russ added a lower spar as well as the three upper ones, but reckons it was probably unnecessary. The choice is yours!

The best flight so far achieved is a rather impressive 75 seconds from a hand launch, though Russ is confident it will also ROG well.


The original plan had an error which unfortunately meant the model had too great a span by about 10 mm. I have now redrawn the plan in CAD (November 2021) and corrected this error. The plan is now presented as a single sheet pdf, suitable for tile printing.

Since I first drew the design it has been pleasing to see quite a few examples built, and they all seem to fly well.

To read and print the pdf file you need Adobe Acrobat Reader, which is a free download from

Click here to download the plan

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